Long-term warming and increased precipitation altered the soil multifunctionality in a temperate desert steppe
Abstract
Soil functional indicators in grasslands are highly sensitive to climate change, particularly in arid regions. However, the impact of long-term warming and increased precipitation on soil functional indicators in a temperate desert steppe remains unclear, and the factors influencing soil multifunctionality (SMF) have not been revealed. After eleven years of warming (Ambient temperature, T0, warming 2 ℃, T1, and warming 4 ℃, T2) and increased precipitation (Natural precipitation, W0, precipitation increases by 25%, W1, precipitation increases by 50%, W2) in the desert steppe, we monitored fourteen soil functional indicators, soil microbial diversity, and SMF. Warming significantly increased SMF. The SMF index (mean ± standard deviation) for the T0W0 and T2W0 treatments were − 0.35 ± 0.27 and 0.10 ± 0.29, respectively. Increased precipitation significantly elevated soil bacterial diversity, but had no significant influence on soil fungal diversity. Pearson correlation analysis indicated a weak correlation between soil microbial diversity and SMF. The random forest analysis further identified NO₃⁻-N, microbial biomass nitrogen, NH₄⁺-N, and total nitrogen as the most important predictors of SMF, with %IncMSE values of 15.30%, 9.72%, 8.62%, and 7.83%, respectively. This study suggested that SMF in the temperate desert steppe was not regulated by soil microbial diversity. Functional indicators related to soil nitrogen content are the primary influencing factors of SMF. Therefore, soil nitrogen content will play a crucial role in assessing the soil service functions of temperate desert steppe under climate change.